1.1 Biological Molecules

Question 1

What are water’s important roles as a biological compound?

Answer 1

1. Being a Solvent
2. Being a Medium for Chemical Reactions
3. For Transport
4. For Hydrophobic and Hydrophilic reactions.

Question 2

Why is water described as being a Polar Molecule?

Answer 2

Due to the electrons being unevenly shared between the oxygen and the hydrogen, the hydrogen has a slight positive charge and the oxygen has a slight negative charge.

Question 3

What are Nitrate’s functions in living organisms?

Answer 3

• The synthesis of Proteins, Nucleic acids and many other Organic Compounds

Question 4

What are Calcium’s functions in living organisms?

Answer 4

• The formation of Middle Lamella (Calcium Pectate) between Cell Walls and normal Cell Wall development
• It is a constituent of Bone, Enamel and Shells
• It activates ATPase during muscle contraction

Question 5

What are Phosphate’s functions in living organisms?

Answer 5

• The synthesis of Nucleic Acids, ATP and some Proteins.
• It is a constituent of Bone and Enamel.
• It is a major component of Cell Membranes

Question 6

What are Potassium’s functions in living organisms?

Answer 6

• Conduction of Nerve Impulses
• It is used in the Na/K (Sodium-Potassium) pump in Active Transport
• Osmotic Balance

Question 7

What are Magnesium’s functions in living organisms?

Answer 7

• It is part of the Chlorophyll molecule
• Used in Bone and Teeth structure
• It is a Cofactor for many Enzymes

Question 8

What are Iron’s functions in living organisms?

Answer 8

• It is the Haem group in Haemoglobin and Myoglobin

Question 9

What are Hydrogen Carbonate’s functions in living organisms?

Answer 9

• It acts as a buffer to control Blood pH

Question 10

What is a Buffer?

Answer 10

A chemical or substance that resists changes to pH and ensures a particular environment maintains a particular pH.

Question 11

Why might Buffers often be used in experiments involving Enzymes?

Answer 11

A Buffer will keep the pH constant, as any change in pH will affect Enzyme Activity

Question 12

What do you call the reaction which Monomers are joined by?

Answer 12

Condensation Reactions

(Removing Water)

Question 13

What do you call the reaction which Monomers are separated by?

Answer 13

Hydrolysis Reactions

(Adding Water)

Question 14

What are the traits of Monosaccharides?

Answer 14

They:
* are Crystalline
* are Soluble
* are Sweet-tasting
* reduce Benedict’s Solution

Question 15

What are the two arrangements of Glucose?

Answer 15

α-glucose
and
β-glucose

Question 16

How do α-glucose and β-glucose differ?

(Think about the Hydroxyl group!)

Answer 16

In α-glucose the Hydroxyl group is below Carbon-1, but in β-glucose the Hydroxyl group is above Carbon-1

(Basically in β-glucose one of its two Hydroxyl groups (the OHs) has been flipped)

Question 17

What is an Isomer?

Answer 17

A substance with the same molecular formula as a substance but a different structural formulae

Question 18

What is a Disaccharide?

Answer 18

Two Monosaccharides joined during a Condensation reaction, held by a Glycosidic Bond.
They can be separated again during a Hydrolysis reaction.

Question 19

Why is a 1,4 Glycosidic bond named this way?

(Refer to the Carbons it forms between!)

Answer 19

Because it is formed between the Carbon 1 of one glucose unit and the Carbon 4 of another.

Question 20

What Monosaccharides is Maltose made up of?

(My Great Granny Sucks Fruit Gums)

Answer 20

Maltose = α-Glucose + α-Glucose

Question 21

What Monosaccharides is Sucrose made up of?

(My Great Granny Sucks Fruit Gums)

Answer 21

Sucrose = Fructose + α-Glucose

Question 22

Describe what Polysaccharides are

Answer 22

Long chains of Monomers joined by Condensation reactions. They are not Sweet and are Insoluble in water.

Question 23

What are the two arrangements of Starch?

Answer 23

1. Amylose
2. Amylopectin

Question 24

What kind of Bonds does Amylose contain between Glucose Molecules?

Answer 24

α- 1,4 Glycosidic Bonds

Question 25

What kind of **Bonds** does **Amylopectin** contain between **Glucose Molecules**?

Answer 25

**α- 1,4 Glycosidic Bonds** and **α- 1,6 Glycosidic Bonds**

Question 26

How is **Amylose** **compact** for **Storage**?

Answer 26

Long **unbranched** chains **coiled** to form **spirals** (these spirals are held in place by **Hydrogen Bonds**) taking up less space compared to other Molecules (like **Amylopectin**).

Question 27

Why is **Amylopectin** a **branched molecule**?

Answer 27

**Multiple Ends** allow the molecule to **Hydrolyse more quickly** than unbranched molecules (like **Amylose**).

Question 28

Why is **Starch** a good **Storage Molecule**? | (Look at Structure & Properties of both **Amylose** & **Amylopectin**)

Answer 28

* It's **Very Compact** - it is aided by the **compact** configuration of **Amylose** * It's **Insoluble** - it has **no Osmotic effect** on its surrounding cells * It's a **Large Molecule** - it is retained in cell and doesn't pass through the membrane * It has **Many Terminal Ends** that are **easily Hydrolysed** due to its **branched** structure

Question 29

What is the name of the **Storage molecule** present in **Plant cells**? | (Technically there are two separate molecules)

Answer 29

**Starch** | (The two are **Amylose** and **Amylopectin**)

Question 30

What is the name of the **Storage molecule** present in **Animal** and **Fungal cells**?

Answer 30

**Glycogen** | (Structurally very similar to Amylopectin)

Question 31

What kind of **Bonds** does **Glycogen** contain between **Glucose Molecules**?

Answer 31

**α- 1,4 Glycosidic Bonds** and **α- 1,6 Glycosidic Bonds**

Question 32

**Glycogen** is even **more highly branched** than **Amylopectin**, why would this be an **advantage** to Animals?

Answer 32

It allows the molecule to be **more readily hydrolysed**, meaning **energy** can be **released more quickly**.

Question 33

What kind of **Carbohydrate** is **Cellulose**?

Answer 33

A **Structural** carbohydrate

Question 34

How are the **molecules** of **cellulose** laid out?

Answer 34

Every alternate **β-glucose molecule** is **'flipped'**

Question 35

The **alternately** placed **β-glucose molecules** allow for?

Answer 35

* **Unbranched Straight Chains** * **H-Bonds** form **cross bridges** between **adjacent chains**, giving a **high tensile strength**

Question 36

Where is **Cellulose** found in **living organisms**?

Answer 36

**Plant Cell Walls**

Question 37

What **elements** do **proteins contain**?

Answer 37

**Carbon**, **Hydrogen**, **Oxygen**, **Nitrogen** and sometimes **Sulfur**.

Question 38

How many different **Amino Acids** are there?

Answer 38

**20**

Question 39

What is it that causes **Amino Acids** to differ from each other?

Answer 39

Having different **R-Groups**

Question 40

In terms of **polymers**, what are **proteins**?

Answer 40

**Large polymers** made of many **monomers (amino acids)**

Question 41

What **groups** do **Amino Acids** consist of?

Answer 41

* An **Amino** Group * A **Carboxyl** Group * An **R-Group**

Question 42

With **Amino Acids**, what **bonds** are formed by **Condensation Reactions**?

Answer 42

**Peptide Bonds**

Question 43

What is a **Dipeptide**?

Answer 43

Two **Monomers (Amino Acids)** joined during a **Condensation Reaction**, held by a **Peptide Bond**. They can be **separated** again during a **Hydrolysis** reaction.

Question 44

In **Amino Acids**, which **groups** does the **condensation reaction** occur between?

Answer 44

The **Amino Group** and the **Carboxyl Group**

Question 45

What is the term for when **many Amino Acids** are joined by **Peptide bonds**?

Answer 45

A **Polypeptide**